Energy audit standards: from regulatory obligation to taking action

Guide to the regulatory energy audit in 2026: what has changed

Our guide to the regulatory energy audit sets out the new requirements and obligations that apply to your company. Two texts have redrawn the framework: the law of 30 April 2025 for the thresholds and the order of 10 July 2025 for the content of the audit.

The industrial energy audit in brief

The regulatory energy audit is an essential tool for assessing and optimising your company's energy needs. Since 1 October 2025, article L233-1 of the French energy code, as amended by law no. 2025-391 of 30 April 2025, uses the legal entity's average annual final energy consumption across all sites [3]. Decree no. 2025-1382 of 29 December 2025 specifies that this average is calculated over the three preceding calendar years [4].

Two thresholds govern the obligation:

• ●
  2.75 GWh per year: an energy audit is required every four years, unless the company already holds a certified energy management system.
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  23.6 GWh per year: the certified energy management system becomes mandatory in its own right.

The criterion of more than 250 employees or 50 million euros of turnover, inherited from European directive 2012/27/EU, therefore no longer determines coverage. The purpose of the audit is unchanged: producing a complete review of energy-intensive utilities and processes, in order to build a precise action plan aimed at saving energy and cutting your CO2 emissions.

What a regulatory energy audit must contain

The order of 10 July 2025, in force since 14 July 2025, sets out how the company energy audit is to be carried out and how the competence of energy auditors is recognised [7]. It refers to the general requirements of standard NF EN 16247-1: 2022, completed by NF EN 16247-2: 2022 for buildings, NF EN 16247-3: 2022 for processes and NF EN 16247-4: 2022 for transport [8].

For industry, the text settles the level expected: "for activities relating to industrial processes, the audit level meets at least level 2 of annex B of standard NF EN 16247-1: 2022" [9]. More specific in nature, this audit level focuses on targeted and detailed improvement measures, in order to optimise energy efficiency in an industrial setting.

The industrial energy audit must therefore include:

• ●
  Consideration of the energy uses accounting for more than 10 % of the site's energy consumption, with a minimum of three uses retained in every case [10];
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  Characterisation of the energy consumption and temperature levels of the various processes [11];
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  Assessment of the temperatures of waste heat discharges [12];
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  Assessment of the opportunities for renewable energy and heat recovery, judged on their cost-effectiveness [13];
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  Classification of energy saving actions into four payback categories [14].

Those four categories are: a payback of one year or less, more than one year and up to three years, more than three years and up to five years, and more than five years [15].

Beyond this regulatory classification, an action plan that can actually be used internally characterises and prioritises each action against several criteria:

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  Emissions reduction (tCO2eq/year)
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  Energy savings (MWh/year)
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  Energy savings (euros/year)
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  Investment costs (thousands of euros)
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  Identified subsidies (thousands of euros)
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  Payback based on net present value (NPV)

The action plan is an obligation in itself. Paragraph II of article L233-1 of the energy code provides that it lists the measures to be implemented where they are technically or economically feasible, and that failure to implement a measure with a payback of less than five years must be justified. The approved plan appears in the company's annual report, together with its completion rate [16].

While it brings you into compliance with the law, this type of audit rarely commits the company to a concrete action plan. Implementation can only be built on a comprehensive action plan covering both utilities and processes, ranking measures to improve energy efficiency and taking economic and environmental criteria into account. When comparing the regulatory industrial energy audit with the advanced audit, the key point is that the first answers legal obligations while the second goes further in operational analysis.

Energy audit methodology in industry: taking action through the advanced audit

Several energy audit methodologies exist for industry: the basic regulatory audit and the advanced audit, each serving different objectives. An advanced energy audit results in a tailored action plan that includes process-specific measures. This type of action plan also improves the identification of available subsidies. Two stages structure it: energy mapping, then building the roadmap.

Energy mapping, a precise analysis for an operational action plan

Energy mapping is a key stage of the advanced audit. It involves taking more numerous and more detailed measurements, in order to provide a comprehensive analysis of energy flows. In practice, it means examining energy needs at each stage of transforming your products, in order to optimise the energy uses that follow from them. The longer the measurement period, the more precise the mapping.

Mapping has to answer three questions about your energy consumption: at which stage, where and when?

At which transformation stage?

From the data collected, a flow diagram representing the activity of the production lines highlights the most energy-intensive process stages and the scope for energy exchanges between them, giving an overall energy view. Power measurements at each item of equipment make it possible to identify improvements both at equipment level and across the process as a whole.

Where on the site?

A topography of the various energy consumers provides the location information needed to assess the feasibility and network costs of the solutions under consideration.

At what time?

The point here is to model the thermal needs of your processes over time. Doing so means taking into account the variables that influence them:

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  Variations in production activity (line speeds, volumes produced);
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  Weather conditions (temperature, humidity);
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  Equipment operating conditions (temperature levels, pressure).

Over a representative period, this modelling breaks energy needs down by temperature level and compares them with the energy produced by the utilities.

Client case: LEMON ENERGY carried out an advanced audit for a large dairy products plant, resulting in a roadmap providing for 20 GWh per year of energy savings. Thanks to this audit report, the site established a precise plan to meet the ambitious targets set by head office. We carried out a complete review of the site, mapping energy performance item by item and providing a schematic diagram for each recommendation. The audit was conducted in coordination with all stakeholders (internal managers and external contractors) and in collaboration with the site's R&D team, in order to check the impact of the proposed solutions on product quality. We supplemented the audit with a feasibility study on heat recovery from wastewater treatment plant effluent. Our entire assignment was 50 % funded by ADEME.

H3: Building an operational roadmap

An audit report generally identifies several improvement opportunities in energy management. Improving your company's energy efficiency may therefore mean ranking them. The advanced audit builds scenarios for implementing the recommended actions, according to your own criteria.

Setting the actions out in a roadmap involves several steps:

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  Categorisation. Actions can be of different kinds, ranging from simple maintenance and process adjustments to more complex reorganisations or targeted investments.
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  Ranking. The priority given to actions varies according to their impact on energy consumption and their economic and technical feasibility.
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  Grouping. The roadmap has to take account of how compatible the actions are with one another in meeting your objectives, considering the savings achievable within a defined capex or payback, along with the planned changes to your installations and your activity.

Building an operational roadmap

An audit report generally identifies several improvement opportunities in energy management. Improving your company's energy efficiency may therefore mean ranking them. The advanced audit builds scenarios for implementing the recommended actions, according to your own criteria.

Setting the actions out in a roadmap involves several steps:

• ●
  Categorisation. Actions can be of different kinds, ranging from simple maintenance and process adjustments to more complex reorganisations or targeted investments.
• ●
  Ranking. The priority given to actions varies according to their impact on energy consumption and their economic and technical feasibility.
• ●
  Grouping. The roadmap has to take account of how compatible the actions are with one another in meeting your objectives, considering the savings achievable within a defined capex or payback, along with the planned changes to your installations and your activity.

Our industrial energy audit advice, drawn from field experience, supports you at every stage of your energy improvement programme. For your action plan to be fully operational, planning how you will measure the impact of the intended actions matters from the audit stage onwards. That means taking stock of the existing data, which then serves to establish energy performance indicators (EnPIs). An EnPI is a ratio that makes it possible to compare and track over time the performance of the energy use it is attached to.

These indicators are built from data from:

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  Sensors (electricity, gas, water, compressed air and so on)
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  Production (machine hours, air flow, water flow and so on)
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  Weather conditions (outdoor temperature, humidity and so on)

A complete energy measurement plan, setting out the data collection and processing methodology along with the list of sensors and energy performance indicators, gives this stage its substance. The order of 10 July 2025 refers in this respect to standard NF EN 17267 on energy measurement and monitoring plans, within the competences required of auditors [17].

Worth knowing: this document is an essential tool for putting effective energy monitoring in place and can support the technical files for energy saving certificates, including standardised operation sheet IND-UT-134, "Système de mesurage d'indicateurs de performance énergétique" [18].

This guide to carrying out an industrial energy audit shows that, beyond regulatory compliance, a thorough approach identifies concrete energy saving opportunities that can be largely funded by the existing support schemes.

To bring your company into compliance with the law, the regulatory audit is a required step. An operational action plan that allows you to meet the ambitious decarbonisation targets set for you rests on the advanced audit, whose cost can be recovered through the energy savings actually achieved. The good news is that ADEME funds voluntary energy audits in industry under the Mon parcours économies d'énergie scheme, up to 80 % for a small company, 70 % for a medium-sized company and 60 % for a large company, over the period from 1 January to 31 December 2026 [19]. Companies subject to the regulatory energy audit, and tertiary premises alone, fall outside this scheme [20]. Contact us to find out more about energy audits and to get support in identifying funding.